Downlaod the Java app combat simulator here:

You may need to install Java for your browser.

In addition to simulating battles the app has the details of enemy fleets for the Ancient Battle Ground missions and many of the Alliance missions.

The simulator appears to be incorrect on a few details of battle unfortunately. It believes that ships will continue to fire at a wounded stack in preference to another stack that was the same size but undamaged. This is a serious error. It also believes that the battlefield repair type flagship modules repair damage suffered on a previous battle if a fleet fights in more than one battle in ABG. They do not (although given time during a single battle they will regenerate a destroyed ship).